The heat conduction tubes of a heat exchanger can experience so-called “hot-spots” where a portion or the entire heat conduction tube can be higher in surface-temperature than other heat conduction tubes. These hot spots can drastically reduce the reliability of the heat exchanger because the material of the heat conduction tube, after prolonged and repeated exposure to such hot spot, can become brittle and crack. Often to delay such failures, the material of the heat conduction tube is composed of expensive specialty materials such as Drawing Quality High Temperature steel alloy, Extra Deep Drawing Steel or similar material. The use of such materials, however, increases the cost of manufacturing the furnace, and only delays the eventual failure of the heat conduction tube.